8.5 TODO: any info on "Create dump tool for write-ahead logs..." in PITR section (1.4)?

Can anyone elaborate (or point me to some additional info) on the 8.5
TODO item in the "Point-In-Time Recover (PITR) section (1.4)": Create dump tool for write-ahead logs for use in
determining
transaction id for point-in-time recovery    This is useful for checking PITR recovery.

I poked around a bit and found some code that "walks" the WAL logs (in
src/backend/access/transam/xlog.c, I think) and I could probably
figure out how to display a WAL log file contents, but I'm hoping
someone can provide some context as to what issue this TODO item is
trying to address (i.e., what output would be useful).